1. Field of the Invention
This invention relates to a brake circuit system for use in vehicles such as dump trucks.
2. Description of the Prior Art
In order to ensure safety during running, various types of brake system have been devised and proposed for use in wheeled vehicles such as dump trucks.
There have so far been known and employed, for example, a brake system comprising two independent brake circuit systems for front left and right hand wheels and for rear left and right hand wheels, the arrangement being made such that even when one of them is damaged or malfunctions, another brake circuit system functions to enable the vehicle to be stopped, and another brake system comprising two brake circuit systems, both of which are adapted to be applied to both front and rear wheel brakes, and which are arranged such that even if one of them is damaged, the remaining circuit system functions to ensure stoppage of the vehicle, etc.
However, the former brake system whose brake circuit system is comprised of two independent brake circuit systems for front wheel brakes and for rear wheel brakes is disadvantageous in that in the event of failure of one of them, the vehicle has to be stopped with the braking force applied only on either front wheel brakes or rear wheel brakes, and as a result, the braking capacity or effect will reduce significantly. In particular, when the brake circuit system for the rear wheel brakes is damaged, fading of the front wheel brakes tends to occur when braking the vehicle, thus making it difficult to effect emergency stop of the vehicle.
Whilst, the latter brake system having two brake circuit systems each of which can be applied to the whole front and rear wheel brakes has been disadvantageous in that when the main brake circuit is damaged it becomes difficult to brake the vehicle.